This research project was designed to examine sensory and motor aspects of swallowing in healthy subjects. Major findings obtained were as follows:1. Sensory aspects)1) The volumes of water judged by the subjects participated )n = 36) were compared with those objectively measured )10.0 and 20.0 mL). The subjects took 10.6±0.86 mL )for 10.0 mL) and 20.2±1.45 mL )for 20.0 mL) of water by the oral cavity, suggesting that normal subjects recognize bolus volume in the oral cavity with high acuity.)2) The optimal and maximum volumes for a swallow were measured in tea and shown that 17.9±1.58 mL and 35.4±2.26 mL, respectively. The easiness of swallowing evaluated by the subjects participated )n = 67) was significantly reduced if the volume for a swallow was increased to 24 mL or that was decreased to 6 mL.)3) The magnitude estimation method was applied to the perception of the weight or volume of bolus in the oral cavity. The estimated magnitudes )Ψ) obtained by the subjects participated )n = 46) were that: Ψ= 2.877S^<1.152> )S, stimulus intensity) for bolus weight and Ψ = 2.944S^<1.151> for bolus volume.2. Motor aspects)1) A simple device was developed to measure laryngeal movement accompanied with swallowing. Coincident recordings, during swallowing, of laryngeal movement by this device with EMG activities indicated that the developed device is useful to analyze temporal aspects of swallowing easily and safely.)2) A measuring and analyzing system of head movement was constructed. Small IC acceleration sensors were used to detect changes in inclination angles of the head and to collect data from nonrestraint subjects. The system measured and analyzed not only conventional cervical ranges of motion but also sequential data of head movement with fluctuations of the body trunk.